The invention relates generally to the treatment of waste products. More particularly, the invention relates to a process and arrangement for the production of fiber substances from waste products such as household waste, agricultural waste, forestry waste and/or organic industrial or commercial waste.
The term "waste" or "waste product" used herein is intended to encompass refuse, rubbish, trash, garbage, debris and the like.
Household waste, agricultural waste, forestry waste and/or organic industrial or commercial waste are normally composed of components which decompose readily under aerobic conditions, other components which are semistable under aerobic conditions and still other components which are difficult to decompose aerobically. Waste of this type accumulated in municipalities is, in known manner, disposed of in incinerating or composting apparatus. It is also known to convert such waste into a biochemically stable fiber substance or into a fiber granulate by means of an aerobic decaying or rotting process followed by sterilization and drying. This is disclosed, for example, in the Swiss Pat. No. 503,576 and in the U.S. patent application Ser. No. 327,234.
During such aerobic degradation or decomposition processes, those substances such as sugar, proteins, starch, fat etc. which readily decompose under aerobic conditions are decomposed almost entirely whereas substances such as cellulose and lignin which, respectively, are semi-stable or difficult to decompose under aerobic conditions are partly or predominantly retained. These semi-stable and difficult to decompose substances may, in the same manner as wood, be considered as biochemically stable, that is, under normal atmospheric conditions, no further degradation by decay or aerobic decomposition is to be expected.
The fiber substance or fiber granulate obtained by the aerobic decomposition is particularly well adapted for mixing with a binder and subsequent pressing or molding into structural panels such as insulating panels, dividing walls, panels for use in furniture etc. However, the fiber substances or fiber granulates obtained by the known processes have the disadvantage that they possess an inherent acidic odor. This is due to the fact that those components of the waste which readily undergo aerobic decomposition are not entirely eliminated during the conversion of the waste into the fiber substance or fiber granulate so that these decompose subsequently thereby giving rise to an odor.